Raghavendra Mudugal (2/12/2016)
From the answer section, it says - "Restore the differential backup from Friday night at 8pm".I have one doubt - do we have to install the diff-backup of just Friday's or the diff- backup from Tuesday's to Friday's?
Just Friday.
For backups, two terms have a more or less standardized meaning: "incremental" (includes all changes since the last full or last incremental), and "differential" (includes all changes since the last full).
Differentials grow larger over time - the differential on Friday includes a lot more changes than the one on Monday. But you only need to restore the last so it's less hassle when restoring.
Incrementals have a more or less equal size (if we assume that a day of work always causes approximately the same amount of change in the database), but you need to restore all of them in sequence.
(One could argue that transaction log backups are incremental. They are incremental in nature, when looking at size and restore requirements, but I would not call them that because the methods used for backuping up the data and restoring are completely different from those of a traditional incremental backup).